Dyeable polypropylene fibers containing acrylate and methacrylate units in polymeric form



DYEABLE POLYPROPYLENE FIBERS CONTAIN- ING ACRYLATE AND METHACRYLATE UNITS IN POLYMERIC FORM Harry W. ,Cooyer,Jr.,.and Frederick B. Joyner, Kingsvport, Tenn., assignors to Eastman Kodak Company,

Rochester, N.Y., incorporation of New Jersey No Drawing. Filed Dec.'2l, 1959, Ser. No. 860,648

- 19 Claims (Cl. 260-897) This invention relates to polypropylene fibers. More particularly, this invention relates to substantially crystalline polypropylene fibers which exhibit excellent dye affinity and fastness properties as well as good resistance to oxidation and weathering. In a more specific aspect, this invention relates to polypropylene fibers which are modified with polymeric acrylic or methacrylic esters.

It is well known that polypropylene, particularly the polypropylene which is partially or completely crystalline, can be spun into synthetic fibers having unusual physical properties. This polymer is, however, subject to inherent disabilities which greatly restrict its utility in the fabrication of general purpose fibers.. For example, a high-molecular-weight, fiber-forming, crystalline polyolefin such as polypropylene, is a relatively insoluble, chemically inert, hydrophobic material. Since it is not readily permeable to water, it cannot be dyed satisfactorily by the ordinary dyeing procedures. Since it is relatively inert chemically, it cannot be permanently dyed even with hydrocarbon soluble dyestuffs. Furthermore, substantially crystalline polypropylene yarnsand fibers cannot be dyed readily with a wide variety of dispersed, premetallized and acid-type dyes, nor can such yarns and fibers be dyed to deep shades having good light and gas tastness. Moreover, the susceptibility of polypropylene fibers to oxidative degradation, instability I toward ultraviolet light and poor weathering characteristics have further limited their utility. Hence, it is most desirable to obtain-fibers free from the above-mentioned disabilities in order to increase their value in the textile Theproblem of obtaining polypropylene fibers having the high tenacity, low elongation and other excellent properties characteristic of such fibers without the accompanying undesirable limitations described above, has plagued prior art workers in this field for many years. However, with the development of the instant invention, we have been able to furnish such a polypropylene fiber.

Accordingly, it is an; object of this invention to provide polypropylene fibers having improved dye atfinity.

Another object-of this invention is to provide polypropylene yarns and fibers with greatly improved dyeing characteristics so that they can be dyed readily with a wide variety of dispersed, premetallized and acid-type dyes which normally will not dye unmodified polypropylene.

Another object is to provide partially or completely crystalline polypropylene yarn and fibers which can be dyed to deep shades with excellent light and gas fastness.

Still another object of this invention ,is to provide polypropylene yarns and fibers having greatly improved resistance to oxidation and weathering in addition to excellent physical properties.

Further objects of the invention will become apparent throughout the following description.

In accordance with this invention it has been found that polymeric blendsof polypropylene and an effective concentration of about 1 to'about 25% and more preferably about 5 to about 15%, by weight based on the polypropylene, of one or more of the acrylate or meth- United States Patent acrylate units, in polymeric form, having the following structure;

' wherein R is hydrogen or methyl and R is an alkyl,

alkoxyalkyl, cycloalkyl, aralkyl or aryl radical desirably containing 1 to 12 carbon atoms, can be spun into high strength fibers and yarns having the same per- The discovery that certain polymeric blends of crystalline polypropylene with polymers of acrylic or methacrylic esters can be spun into high strength fibers and yarns having excellent afiinity for dispersed and premetallized dyes as well as excellent light and gas fastness was quite surprising since it could not have been predicted from the prior art. .According to the prior art, poly(methylmethacrylate), when used as a modifier for acrylic fibers, such as acrylonitrile fibers, imparts only a low atfinity for dispersed dyes and, even so, the dyed materials obtained thereby ex- 'hibit very poor light fastness.

Although unmodified polypropylene shows virtually no afiinity for dyestults, it can be dyed with some dyes to weak shades having, however, very poor fastness Surprisingly, it 7 properties as mentioned hereinbefore. has been found that the shades produced by a given dye on the unmodified polypropylene yarn and on the modifiers themselves were quite different from the shades produced by the same dye on the modified polypropylene yarns of this invention. dicates that the fibers spun from the polymeric blends described above possess characteristics which ordinarily would not have been expected in fibers spun from simple mixtures of polymeric materials. In this connection, it

was also discovered that the modified polypropylene fibers described herein were 'from 3 to 4 times more resistant to oxidative degradation than fibers obtained from unmodified polypropylene.

The modified polypropylene fibers of this invention are also more stable toward ultraviolet light'and weathering conditions than unmodified polypropylene fibers. The

reason for the increased stability of the modified polypropylene fibers toward oxidation, light and weathering is not completely understood. It is possible, however, that free radicals generated from the polymeric modifiers combine with free radicals produced from the polypropylene to prevent chain reactions which would other- T I wise result in rapid deterioration of the polyolefin. It is possible that the polymeric modifiers may also be etfective in absorbing actinic radiant energy which otherwise i could activate free-radical mechanism of decomposition in the polypropylene.

These modified polypropylene fibers and yarns may be further stabilized against thermal breakdown and weathering with any of the conventional stabilizers for polyolefins. It is usually convenient to add such stabilizers to the polymeric blends before spinning into fibers.

The modified polypropylene fibers and yarns of this invention may be drawn to give the same high tenacities,

low elongations and other excellent properties found in unmodified polypropylene fibers and yarn. This is quite surprising, since the polymers of acrylic and methacrylic esters are substantially non-crystalline when prepared by conventional methods and, as a result, give fibers which possess low tenacities, high shrinkage properties, and no commercial value. It would have been predicted, con- 3,156,743- Patented Nov. 10, 1964 I This unpredictable result intrary to fact, that these materials, when used to modify polypropylene for fibers and yarn, would have deleteriously affected the properties of the yarn.

Another unpredictable feature of this invention is the fact that the polymeric acrylic and methacrylic esters used to modify polypropylene could not be used satisfactorily to modify polyolefin fibers in general. For example, when these modifiers were ineorpoarted into high density or into conventional polyethylene, they were found to be substantially incompatible. Thus, a blend of polyethylene (90 parts) and poly(methylmethacrylate) (10 parts) on melt spinning gave fibers which 'were badly segmented. When these fibers were drafted, fibrillation resulted, giving a substantially useless product in contrast to the polypropylene fibers of our invention which showed no fibrillation when drafted.

A still further unpredictable feature of this invention is the fact that the nitriles and amides of the acrylates and methacrylates employed in this invention failed to impart the desired characteristics to polypropylene yarns and fibers. Thus, ineffective modifiers for polypropylene fibers included polymethacrylonitrile, polyacrylamide and polymethacrylamide.

According to the practice of the invention, the monomers which are suitable for polymerization into the useful polymeric compositions for blending with polypropylene in accordance with this invention are those represented by the generic formula:

wherein R is hydrogen or methyl and R is an alkyl, alkoxyalkyl, cycloalkyl, aralkyl or aryl radical desirably containing 1 to 12 carbon atoms.

The monomeric units which are described herein can be present either in the form of a homopolymer or in the form of a copolymer of the desired acrylate or methacrylate with another acrylate or methacrylate or with a vinyl pyridine or N-substituted acrylamide as hereinafter defined.

Useful copolymersthen, can be composed of two or more different acrylate or methacrylate units, as set forth hereinbefore, or of these materials and one or more vinyl pyridine or N-substituted acrylamide units, as hereinafter described. Monomeric units of the latter type are those derived from (1) vinyl pyridines having the formula:

C-CH; N

wherein R is hydrogen or methyl, R is a lower alkyl group desirably containing 1 to 4 carbon atoms, n is an integer from to 4, and (2) N-substituted acrylamides having the formula:

R o CH -(il-(il-NWR wherein R is hydrogen or a lower alkyl group desirably containing 1 to 4 carbon atoms; R is hydrogen or an alkyl, cycloalkyl, aralkyl or aryl group desirably containing 1 to 18 carbon atoms and R is an alkyl, cycloalkyl, aralkyl or aryl group desirably containing 1 to 18 carbon atoms. Suitable monomers include 2-vinyl pyridine, 3- vinyl pyridine, 4-vinyl pyridine, 5-ethyl-2-vinyl pyridine, 2-methyl-5-vinyl pyridine, 2-methyl-6-vinyl pyridine, 2,4- dimethyl-G-vinyl pyridine, 5-propyl-2-vinyl pyridine, S-isobutyl-Z-vinyl pyridine, 2-isopropenyl pyridine, N-isopropylacrylamide, N-isopropylmethacrylamide, N,N-dimethylacrylamide, N-phenylacrylamide, N-cyclohexylacrylamide, N-butylacrylamide, N,N-diethylacrylamide, N- ethylacrylamide, N-methylacrylamide, N-methyl-N-phenylacrylamide, and N-dodecylacrylamide.

Hence, the polymeric modifiers of this invention may also be described as polymers containing recurring units having the general structure:

wherein R and R are as defined above, Z is the residue of an unsaturated, polymerizable vinyl pyridine or N-substituted acrylamide, as described above, and x and y are integers which will provide a homoor copolymer having D,

a molecular weight of at least 1000. It is obvious that the nature of the unsaturated, polymerizable vinyl pyridine or N-substituted acrylamide units are subject to wide variation. The truly important feature of the modifier is that acrylate or methacrylate units of the type described above be present therein, preferably in amounts of from 50 to mole percent.

Those radicals which can be present in the ester group of the monomeric acrylate or methacrylate, as described by R' in the above formulas, are subject to wide variation and include, for example: methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl, 2-ethylhexyl, nonyl, lauryl, dodecyl, cyclopentyl, cycloheptyl, cyclohexyl, trimethylcyclohexyl, benzyl, phenylhexyl, phenyl, trimethylphenyl, diphenyl, methoxyethyl, ethoxybutyl, methoxylauryl and ethoxyethyl.

The monomeric units described above may comprise less than 50 mole percent, e.g., 40, 30, 20, or even 10 mole percent of the polymeric modifier, but mole percentages of 50 to 100 percent are preferred particularly where good dye afiinity for dispersed dyes is desired.

It has been found that blends of crystalline polypropylene with the polymeric modifiers described can be melt spun into high strength yarns which can be dyed to deep, light and gas-fast shades by meansvof dispersed and premetallized dyes. The dyeing process can be carried out using conventional procedures either with or without carriers. The polypropylene blends can contain from 1% or less to 25% or more, by weight of the homoor copolymeric modifier, although the preferred concentration of modifier is from 5 to 15%. However, there are special situations which may warrant the use of 30 or perhaps even 40% by weight based on the blend, of certain of the copolymeric modifiers disclosed. Furthermore, even though as little as 1% by weight based on the blend, of the specified polymeric modifiers will impart dye affinity to the fibers, it is preferred that amounts of at least 5% be employed, particularly where deep shades are desired. Polypropylene blends of this type can be melt spun at temperatures ranging from 25 to 65 C. lower than are necessary to melt spin pure polypropylene.

Some specific polymeric modifiers useful in the practice of this invention are:

Poly(methyl methacrylate) Poly(ethyl methacrylate) Poly(isopropyl methacrylate) Poly(n-propyl methacrylate) Poly(n-butyl methacrylate) Poly(isobutyl methacrylate) Poly (tert-butyl methacrylate) Poly(n-hexyl methacrylate) Poly(lauryl methacrylate) Poly(cyclohexyl methacrylate) Poly (benzyl methacrylate) Poly(phenyl methacrylate) Poly(methyl acrylate) Poly(n-propyl acrylate) Poly(n-butyl acrylate) Poly(2-methoxyethyl acrylate) Poly(Z-ethoxyethyl acrylate) Poly(Z-ethylhexyl acrylate) 75/25 copolymer methyl acrylate/ethyl methacrylate 20/80 copolymer ethyl acrylate/N-tert-butylacrylamide- I 75/25 copolymer ethyl acrylate/2-methyl-6-vinyl pyridine 50/50 copolymer 2-vinyl pyridine/ethyl acrylate 50/ 50 copolymer methyl methacrylate/3-isop1fopenyl pyridine 60/30/10 copolymer N,N-dimethylacrylamide/N-isopropenyl acrylamide/ methyl methacrylate No'rE.-The integers given to indicate the copolymer composition are based on mole percent here and throughout the specification.

Blends of crystalline polypropylene with one or more of the polymeric modifiers may be prepared in any desired manner, whether it be mechanical mixing, coprecipitation or other blending method, e.g., they can be prepared at elevated temperatures on rolls, in a Banbury mixer or any other suitablejtype of processing equipment, or they can be prepared by multiple extrusion techniques. The polymeric modifiers can have a molecular weight of 1000 and higher depending on the particular blend properties desired and the blending method employed. It is to be understbod, of course, that any polymeric modifier having a molecular Weight in excess of 1000 which is capable of introducing the specified percent by weight, based on polypropylene, of the described acrylate or methacrylate units into the blend is within the scope of our invention.

Usually, it is preferable to prepare the modified polypropylene compositions from polypropylene having a conditioned density above 0.90 and an inherent viscosity in tetralin at 145 C. of from 0.9 to 1.2. Conditioned density, as used herein, refers to the density determined on a sample which has been annealed in anattempt to obtain maximum crystallinity. A conventional annealing procedure involves placing the sample in a tube, heating under high vacuum or in a nitrogen atmosphere to just below the softening point, and allowing the sample to cool slowly. Polypropylene having inherent vis' cosities above 1.2 can be used in preparing the modified compositions, but then it is usually necessary to degrade these compositions thermally to a lower viscosity in order to realize optimum melt spinning characteristics and fiber properties. The'temperatures required for this degradation ars usually above 300 C. and often result in an appreciable loss of modifier through depolymerization. Polypropylene of inherent viscosity less than 0.9 can be used in preparing modified compositions for melt spinning, but it does not afiord fibers having optimum physical properties.

The modified polypropylene compositions described herein may be spun into fibers having the desired characteristics by the conventional spinning procedures, e.g., melt spinning, dry spinning, Wet spinning or extrusion through a suitable die. Furthermore, these modified polypropylene compositions can be formed into the various cross-sections, e.g., cloverleaf, Y-section etc., by employing spinnerettes or dies having appropriately shaped orifices.

The following examples are introduced to illustrate but not necessarily to limit our invention. 1

Example 1 6 a neutral dyeing premetallized dye [Color Index, volume 4, Second Edition (1956), page 4326], in the aqueous dye baths at boil for 1 hour. Even deeper shades were obtained by using carriers such as benzyl n-butyrate. All samples showed excellent fastness to ultraviolet light in a fadeometer for 20 hours.

I i H III IV V Percent. Polypropylene 100 95 90 85 Percent Poly (methyl methacrylatc) 5 10 15 20 Yarn Viscosity 0. 0.97 0. 91 0. S5 0. 89 Total Denier 223 196 164 153 162 Tenacity, gJden 7.33 5. 23 7.25 6.80 7.25 Elongation, percent 18 2B 17 18 14 Elastic modulus, g./den 63 02 71 59 79 Example 2 Although the methyl esters of acrylic and methacrylic acid are preferably used, the other alkyl esters as defined herein can be used with excellent results. Thus, a mixture of 9 parts of crystalline polypropylene (inherent viscosity=l.05 and density=0.9l4) and 1 part of poly(nbutyl methacrylate) was prepared by evaporating a toluene solution of the latter onto pellets of the polypropylene in a conical mixer under vacuum. The solvent-free mixture was then melt extruded into /a in. rod and then was chopped into pellets having a length of about A; in. The resulting composition was readily melt spun into 34 filament yarn at a spinning temperature of 230 C. The unmodified polypropylene required a melt spinning temperature of 280 C. for optimum spinning characteristies. The modified polypropylene yarn obtained above was knitted into a sock or tube which was used in dyeing tests. Excellent dye atfinity for dispersed and premetallized dyes was demonstrated by the deep shades with Isolan Red B, a neutral dyeing premetallized dye [Color Index, volume 4, Second Edition 1956), page 4326], 4-

anilino-3-nitrobenzenesulfonamidc, 4-(4-methyl-2'-nitrobenzene)-3-methyl-5-pyroazolene, 4 [4' (benzeneazo)- .benzeneazo] -phenol, 1'-amino 4 hydroxy 2 phenoxy- ,ethyl acrylate).

Example 3 Acrylate and methacrylate homopolymers are conveniently used, but copolymers, as described herein, are also suitable in the amounts and proportions also defined herein. The procedure of Example 2 was followed except that the poly(n-butyl methacrylate) was replaced with a 50/50 copolymer n-butyl/isobutyl methacrylate. The resulting yarn had a tenacity of 5.2 g./den., an elongation of 27% and an elastic modulus of 40g./den. Knit tubes of this yarn dyed to deep shades with 4-(4-,8-hydroxyethylanilino)-5-nitro-1,8 dihydroxy anthraquinone and Isolan Red B, a neutral dyeing premetallized dye [Color Index, volume 4, Second Edition (1956), page 4326], in the aqueous dye baths at boil for 1 hour. A sample of the unmodified polypropylene in the form of a knit tube showed comparatively little or no tendency to take up these dyes. When a carrier was used, the unmodified yarn dyed to light shades with poor fastness properties which showed distinct differences in actual color when compared with the corresponding samples of dyed modified yarn.

Other copolymers which gave similar results when used in place of the N-butyl/isobutyl methacrylate copolymer as above were 75/25 copolymer methyl acrylate/ethyl methacrylate, 50/ 50 copolymer methyl/n-butyl methacrylate, 80/20 copolymer methyl methacrylatc/ethyl acrylate and a 60/40 copolymer methyl/cyclohexyl methacrylate. In these instances, the amount of modifier was selected to give an effective concentration of 1% to 25% Technical Manual and Yearbook of the American Association of Textile Chemists and Colorists, volume XXVIII, page 205). Deep shades were both light and gas fast and were readily obtained.

of acrylate or methacrylate based on the polypropylene. 5 Example 7 Example 4 Several compositions comprising crystalline polypropyl- A mixture of 9 parts of crystalline polypropylene (inene (inherent viscosity 1.0, density 0.912) and a 20/80 herent viscosity 1.05 and density 0.914) and 1 part of copolymer ethyl acrylate/N-tert-butylacrylamide were 50/50 copolymer methyl methacrylate/3-isopropenyl 10 prepared by mechanically blending granules of the two pyridine was prepared by evaporating a toluene solupolymeric materials followed by melt extrusion and retion of the latter onto pellets of the polypropylene in a pelleting of the resulting compositions. These composiconical mixer under vacuum. The solvent-free mixture tions were then melt spun into 34 filament yarns. Knit was then melt extruded into V8 in. rod and then chopped tubes prepared from these yarns all dyed to deep shades into pellets having a length of about V8 in. The resultwith 4-(4'-fl-hydroxyethylanilino)-5-nitro-1,8-dihydroxying composition was readily melt spun into 34 filament anthraquinone and Isolan Red B, a neutral dyeing preyarn at a spinning temperature of 265 C. The unmodimetallized dye [Color Index, volume 4, Second Edition fied polypropylene required a melt spinning temperature (1956), page 4326], in aqueous dye baths at boil for 1 of 280 C. for optimum spinning characteristics. The hour. The knit fabric also dyed well with Wool Fast modified polypropylene yarn obtained above was knitted Blue BL (Color Index 833) and Du Pont Milling Red into a sock or tube which was used in dyeing tests. SWG (1952 Technical Manual and Yearbook of the Excellent dye afiinity for dispersed, premetallized and American Association of Textile Chemists and Colorists, acid dyes was demonstrated by the deep shades obtained volume XXVIII, page 205) under similar conditions. with Isolan Red B, a neutral dyeing premetallized dye, Even deeper shades were obtained by using carriers such [Color Index, volume 4, Second Edition (1956), page as benzyl n-butyrate. All samples showed excellent fast- 4326], Wool Fast Blue (Color Index 833) and 4-(4'- 8- mess to ultraviolet light in a fadeometer for 2-0 hours. A hydroxyethylanilino)-5-nitro-1, 8 dihydroxy anthraquisample of the unmodified polypropylene showed comparanone, tively little tendency to take up these dyes.

Similar results were obtained when a 60/30/10 co- Example 8 polymer 2-methyl-5-vinyl pyridine/3-vinyl pyridine/nbutyl methacrylate was used in place of the 50/ 50 co- A 9 P 9 Parts of crystallme P yp py polymer methyl methacrylate/3-isopropenyl pyridine, as herem vlscoslty and y 0914) and 1 P above 50/30/20 copolymer N,N-dnnethylacrylamide/N-isopro- Example 5 pyl-acrylamide/methyl methacrylate was prepared by me- I chanically blending granules of the two polymers. The ggg g g g g g ffigfi f ig fg g i mechanical blend was then melt-extruded into A; in. rod {din p lyced mar fi and then was chopped into pellets having a length of i g 52 1 lridine The E i S 5 about /a in. The resulting composition was readily melt a y Y PY g X a spun into 34 filament yarns at 'a spinning temperature of tenacity of 7.0 g./den., an elongation of 20A: and an c The 40 unmodified polypropylene requlred a melt elastic modulus of 81 g./den. knit tubes of this yarn o v spinning temperature of 280 C. for optimum spinning dyed to deep shades with 4-(4 -B-hydroxyethylaml1no)-5- characteristics Th I e modified polypropylene yarn obnitro-l,8-dihydroxy anthraqutnone and Wool Fast Blue mined above W k as mtted into a sock, or tube, which dyed BL (Color Index 833) in aqueous dye-baths at boil for to deg Shades 4 h d h l T 5 1 hour A sample of the unmodified polypro le in WI y roxyet y am muo- PY ne the form of a knit tube showed com arativel little or 18 'dlhydroXy anthmqumone Isolan Red B a neutral 9 y dyeing premetallized dye [Color Index, volume 4, Secno tendency to take up these dyes. When a carrier was 0nd Edition (1956) page 4326], 1n aqueous dye baths used, the unmodified yarn dyed to light shades with poor at boil for 1 hour A 1 f th d 1 fastness properties which showed distinct differences in samp-e 0 e unmo 1 8 p0 p 1cm a1 color when Com med with the cones Ondin Sam pylene 1n the form of a knit tube showed comparatively l fd d Odfi d p P g little or no tendency to take up these dyes. When a carp m 1 e 5 rier was used, the unmodified yarn dyed to light shades Smnlar results were obtained when a /50 copolymer with oor fast 5 r h h d (ff 2-vinyl ridine/eth l acr late was used i lac f the p e S p oper w w s lstmct Dy 3' y 11 P e 9 f 1 1 75/25 Co 01 mer 6th lacr ],lte/2 meth 1 rid. erences 1n actua c0 or when compared with the correqs abovcp y y y y y W l sponding samples of dyed modified yarn.

, Example 6 v Example 9 Blends of crystalline polypropylene with a 50/50 co Blends of crystalline polypropylene with a 25/75 c0- polymer methyl methacrylate/Z-methyl-5-vinyl pyridine polymer methyl methacrylate/N,N-dimethylacrylamide were prepared by melt extruslon of the mechanical mixwere prepared by melt extrusion of the mechanical mixtures of the two resins. These blends were then melt ture of the two resins. These blends were then melt spun into 34 filament yarns having the properties shown 6 spun into 34-filament yarns having the properties shown below. below.

I II III I II III Polypropylene, percent 92 83 75 Propylene, percent 97 82 50/50 copolymer methylmethaerylatel2-n1ethy14r 25/75 copolymer methyl Inethacrylatc/N,N-(livinyl pyridine, percent 8 17 25 methylaerylamide, percent 3 18 25 1arnvisc0s1ty 0.86 0.89 0.85 Yarn Inherent Viscosity 1.01 0,93 (7.85 Total Denler 152 162 184 Total Denier"... 14B 178 176 Tcnaelty,g./den 7. 24 7.25 6. 82 Tenaclt v,g./den 8. b5 6. 97 6.74 Elongation, percent" 15 14 21 Elongation, pereen 16 20 23 Elastic modulus, g./den 81 79 60 7() Elastic modulus, g./den 102 71 62 Knit tubes fashioned from these yarns were readily Knit tubes fashioned from these yarns were readily dyed with 4-(4'-,B-hydroxyethylanilino)-5-nitro-1.S-dihydyed with 4-(4-[1-hydroxycthylanilino)-5 nitro-l.8-dihydroxy-anthraqumonc as well us With Wool Fast Blue BL droxy anthraquinonc and Isolan Red It, a neutral dyeing (Color Index 833) and Du Pont Milling Red SWG (I952 75 premetallizcd dye lColor Index, volume 4, Second l-Idilion (1956), page 4326] as well as with other dispersed and premetallized dyes. Good dyeability was noted also when these materials were subjected to dyeing with acid and direct dyes. Deep shades whichwere both light and gas fast were readily obtained.

Thus, by means of this invention, substantially crystalline polypropylene yarns and fibers having improved dye atfinity, excellent light and gas fastness and increased stability may be obtained. The improved polypropylene fibers of this invention may be used in the same manner as conventional polypropylene fibers; for example, they can bewoven into wool-like blankets or used in the production of automobile seat covers and marine hawsers that are almost as strong as nylon and somewhat cheaper.

The invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

We claim:

1. Polypropylene fiber exhibiting excellent dye afiini-ty, light and gas fastness, resistance to oxidation and weathering, said fiber containing a polymeric modifier selected from the group consisting of homopolymers of (l) a monomer having the formula:

O CHpil-PJ-O R wherein R is a member selected from the group consisting of hydrogen and methyl and R is a member selected from. the group consisting of. alkyl, alkoxyalkyl, cycloalkyl, aralkyl and aryl radicals containing 1-12 carbon atoms, and copolymers of a monomer having said formula with a member selected from the group consisting of (A) different monomers having said formula and (B) vinyl pyridine monomers having the formula:

(3:03, n wherein R is a member selected from the group consisting of hydrogen and methyl and R is a lower alkyl group containing 1-4 carbon atoms, n being an integer from to 4, and (C) N-substituted acrylamide monomers having the formula:

I v R4 0 CH,=( JiiNR R wherein R is a member selected from the group consisting of hydrogen and lower alkyl groups containing 1-4 carbon atoms, R' is a member selected from the group consisting of hydrogen, alkyl, cycloalkyl, aralkyl and aryl groups containing 1-18 carbon atoms and R is a member selected from the group consisting of alkyl, .cycloalkyl, aralkyl and aryl groups containing 1-18 carbon atoms;

2. Polypropylene fiber exhibiting excellent dye aflinity, light and gas fastness, resistance to oxidation and weathering, said fiber containing about 1 to about 25%, by weight, based on polypropylene, of a polymeric modifier selected from the group consisting of homopolymers of (1) a monomer having the formula:

CH,=O-ii-0 R' wherein R is a member selected from the group consisting of hydrogen and methyl and R is a member selected from the group consisting of alkyl, alkoxyalkyl, cycloalkyl, aralkyl and aryl radicals containing l-12 carbon atoms, and copolymers of a monomer having said formula with a member-selected from the group consisting of (A) different monomers having said formula and (B) vinyl pyridine monomers having the formula:

wherein R is a member selected from the group consistv ing the formula:

I consisting of hydrogen, alkyl, cycloalkyl, aralkyl and aryl wherein R is a member selected from the group consisting of hydrogen and lower alkyl groups containing 1-4 carbon atoms, R is a member selected from the group consisting of hydrogen, alkyl, cycloalkyl, aralkyl and aryl groups containing l-18 carbon atoms and R- is a member selected from the group consisting of alkyl, cyclo- 5. The fiber of claim 2 in which the polymeric modifier is a copolymer of a monomer (1) with a monomer 1 6. The fiber of claim 2 in which the polymeric modi- 7 fier is a copolymer of a monomer (1) with a monomer 7. The fiber of claim 2 in which the polymeric modifier is a copolymer of a monomer (l) with a monomer 8. A blend comprising solid polypropylene and about 1 to about 25%, by weight, based on polypropylene, of

a polymeric modifier selected from the group consisting of homopolymers of (l) a monomer having the formula:

0 CH =0-&-OR

1'1. wherein R is a member selected from the group consisting of hydrogen and methyl and R is a member selected from the group consisting of alkyl, alkoxyalkyl, cycloalkyl, aralkyl, and aryl radicals containing 1-12 carbon atoms, and copolymers of a monomer having said formula.

with a member selected from the group consisting of (A) different monomers having said formula and (B) vinyl pyridinemonomers having the formula:

. v $=CHI N wherein R is a member selected from the group consisting of hydrogen and methyl and R is a lower alkyl group containing1-4 carbon atoms, n being an integer from O to 4, and (C) N-substituted acrylamide monomers having the formula:

wherein R is a member selected from the group consisting of hydrogen and lower alkyl groups containing l-4 carbon atoms, R is a member selected from the group groups containing l-l8 carbon atoms and R is a member selected from the group consisting of alkyl, cycloalkyl,

aralkyl and aryl groups containing l-l8 carbon atoms.

9. The blend of claim 8 which contains about 5 to 1 1 about 15%, by weight, based on polypropylene, of the polymeric modifier.

10. The blend of claim 8 in which the polymeric modifier is a homopolymer of (1).

11. The blend of claim 8 in which the polymeric modifier is a copolymer of a monomer of (1) with a monomer of (A1 1 12. Polypropylene fiber exhibiting excellent dye aflinity, light and gas fastness, resistance to oxidation and weathering, said fiber containing about 1 to about 25 by weight, based on the fiber, of poly(methyl methacrylate.)

13. Polypropylene fiber exhibiting excellent dye affinity, light and gas fastness, resistance to oxidation and weathering, said fiber containing about 1 to about 25% by weight, based on the fiber, of poly(cyclohexyl methacrylate).

14. Polypropylene fiber exhibiting excellent dye affinity, light and gas fastness, resistance to oxidation and weathering, said fiber containing about 1 to about 25 by weight, based on the fiber, of poly(benzyl methacrylate).

15. Polypropylene fiber exhibiting excellent dye afiinity, light and gas fastness and resistance to oxidation and weathering, said fiber containing about 1 to about 25 by weight, based on the fiber, of poly(2-methoxyethyl acrylate).

16. A blend comprising solid polypropylene and about 1 to about 25% by weight, based on the polypropylene, of poly(methyl methaerylate).

12 17. A blend comprising solid polypropylene and about 1 to about 25% by weight, based on the polypropylene, of poly(cyclohexyl methacrylate).

18. A blend comprising solid polypropylene and about 1 to about 25 by weight, based on the polypropylene, of poly(benzyl metbacrylate).

19. A blend comprising solid polypropylene and about 1 to about 25 by weight, based on the polypropylene, of poly(2-methoxyethyl acrylate).

References Cited in the file of this patent UNITED STATES PATENTS 

2. POLYPROPYLENE FIBER EXHIBITING EXDELLENT DYE AFFINITY, LIGHT AND GAS FASTNESS, RESISTANCE TO OXIDATION AND WEATHERING, SAID FIBER CONTAINING ABOUT 1 TO ABOUT 25%, BY WEIGHT, BASED ON POLYPROPYLENE , OF A POLYMERIC MODIFIER SELECTED FROM THE GROUP CONSISTING OF HOMOPOLYMERS OF (1) A MONOMER HAVING THE FORMULA:
 5. THE FIBER OF CLAIM 2 IN WHICH THE POLYMERIC MODIFIBER IS A COPOLYMER OF A MONOMER (1) WITH A MONOMER (A).
 6. THE FIBER OF CLAIM 2 IN WHICH THE POLYMERIC MODIFIER IS A COPOLYMER OF AMONOMER (1) WITH A MONOMER (B).
 7. THE FIBER OF CLAIM 2 IN WHICH THE POLYMERIC MODIFIER IS A COPOLYMER OF A MONOMER (1) WITH A MONOMER (C).
 12. POLYPROPYLENE FIBER EXHIBITING EXCELLENT DYE AFFINITY, LIGHT AND GAS FASTENSS, RESISTANCE TO OXIDATION ANDWEATHERING, SAID FIBERCONTAINING ABOUT 1 TO ABOUT 25% BY WEIGHT, BASED ON THE FIBER, OF POLY(METHYL METHACRYLATE). 